God can move matter to form directly, because the passive power of being can be immediately actualized by the active power which holds it subject. Since matter, therefore, is subject to the Divine Power, inasmuch as it is created by God, much more can it be actualized by Him.
Thus God can move all bodies immediately, and it is an error to say that God cannot, by Himself alone, produce all the determinate effects which flow from any created cause whatever. For it is one and the same thing to impress form, to dispose to form, and to give motion according to form; and since God can impress form in matter immediately He can also move a body according to any species of motion.
In like manner God moves the created intellect, both by giving to it the power of understanding and by impressing intelligible species. For God is the First Intelligence, and the Cause of all intellectual power; consequently of all other intelligences, which He strengthens and elevates.
The will is also moved by God; but as its object. For the will is moved by every good, but by God alone sufficiently and efficaciously, because the object of the will is universal good, and this is found in God only, not in particular creatures. Therefore the power of willing comes directly from God; for universal good is the object, and to will is simply to be inclined to an object, while the inclination to universal good is from the First Mover, by Whom it is proportioned to the final end.
And God works in everything, yet so that each object has its proper operation. Otherwise the order of things would be destroyed, and God would be manifested as wanting in power to produce causes which would act in co-operation with Him, and the operative power of things would fail. He works also according to every species of cause. First, as End, inasmuch as every operation is for the attainment of some good, real or apparent, and nothing can appear such except as participating in some similitude to the highest good; consequently God is the Cause of every operation as End. Secondly, as Agent; for the first agent moves the second, so that all act in virtue of God Himself Thirdly, as Form; for God is Cause, not only as giving and applying the principles of actions, but as giving, preserving and applying forms which are the principles of actions. Thus God is the Universal Cause of the being of all things, and works intimately in them. Material causes are not admitted, for matter does not act, but is acted upon.
There is, moreover, a twofold order in things. One consists in dependence upon the First Cause, against which God cannot act, because to do so would be to oppose His own foreknowledge; which is impossible. The other consists in the dependence of things upon second causes; and God can counteract these because such order is subject to Him, inasmuch as it proceeds according to the choice of His Will. For the superior cause is not subject to secondary causes, and since all are subject to God, He can institute other orders, either by producing the effects of second causes without them, or by producing other effects to which such causes do not extend.
Those things which are done by God beyond the known order of causes are called miracles, on account of the wonder they excite; for they have an unknown cause manifested by the effect. But a wonder differs from a miracle inasmuch as that may be a wonder to one which is not so to another; as an eclipse is a wonder to the peasant, but not to the astronomer; whereas a miracle has a simple cause hidden from all. Therefore, one miracle is said to be greater than another, not in respect of the Divine Power, but in proportion as it exceeds the powers of Nature.
Things may exceed the power of Nature in three ways: first, according to the substance of the thing done; as when the sun goes backwards, which constitutes the first class. Secondly, according to the matter in which it is done; as raising the dead: for Nature can give life, but not to the dead; and such are called miracles of the second class. Thirdly, according to the mode by which the miracle is done; as when a fever is cured without the use of natural means, or rain is condensed in the air; for although these things exceed the power of Nature according to their mode and order, they may be produced gradually by natural means; therefore such hold the lowest place in the order of miracles.
- text taken from Compendium of the Summa Theologica of Saint Thomas Aquinas, by Bishop Berardus Bongiovanni